Heart disease is the most common cause of death in the Western world. More than a third of Americans will die from it. To treat the disease, 30 million people in this country now take a powerful class of drug called statins, which lower cholesterol, wiping out one of the risk factors. Statins are now the most prescribed medication in the world. But not without controversy. A small number of people experience side effects from statins, and some research suggests they are overprescribed.

Dr. Steven Nissen is cardiology chair of the Cleveland Clinic; that's one of the foremost heart research facilities in the country working on treatments for the epidemic of heart disease.

DR. STEVEN NISSEN: If you add up all the other causes of death, in some countries heart disease is actually greater than all other causes combined. That means it's 50 percent or more of all the mortality. It's not quite that high in the United States, but it's pretty close.

WERTHEIMER: And of the kinds of medications that are available, where do statins fit into that?

NISSEN: Certainly, statins are enormous. They are more controversial than they should be. We have high-quality clinical research trials involving several hundred thousand patients. And in most high-risk populations, they lower the risk of a heart attack, stroke or death by anywhere from 25 to 35 percent.

WERTHEIMER: What about the side effects?

NISSEN: Serious side effects are very rare, fortunately. What is not quite so rare is aching of muscles or even a little bit of muscle weakness. It's not serious but it can be severe enough that patients will complain of it and they won't want to take the drugs.

WERTHEIMER: Now, this drug is the most prescribed drug in the United States. Is that a good thing? Should so many people be taking it?

NISSEN: I believe that they should. These drugs have been so effective that some have advocated giving them to virtually everybody over the age of 45 or 50. That is not wise advice, but the vast majority of people who are taking statins are people in whom they are indicated.

WERTHEIMER: Statins are very effective at what they do - control high cholesterol - but treating heart disease is more complex than that. We visited Dr. Ken Lee. He's a cardiologist here in Washington who sees about 70 heart patients a week. One of them is Eric Swendson, who is retired; he has been Dr. Lee's patient since he had a heart bypass 17 years ago.

DR. KEN LEE: Come on back, Eric.

WERTHEIMER: Eric Swendson is rangy, thin, relatively fit.

LEE: All right. How you been doing?

ERIC SWENDSON: I've been doing pretty good.

LEE: No chest pain?

WERTHEIMER: Swendson takes statins to keep his cholesterol levels low. Dr. Lee thought the levels could be lower still and suggested a stronger statin. And they discussed smoking.

LEE: So, you're still smoking?

(SOUNDBITE OF CLEARING THROAT)

SWENDSON: Yes. One pack a day.

LEE: No. No. I'm good on that. I'm just trying to figure out if there's anything new that I can offer you. I mean, at some point in time you just got to let me know when you're interested in stopping.

SWENDSON: Well, at least I buy cigarettes by the pack.

LEE: I'm going to keep nagging you.

SWENDSON: OK. I'm just going to keep at it.

LEE: That's fine. That's fine.

WERTHEIMER: Smoking is very high on the list of risk factors for heart disease. Dr. Nissen of the Cleveland Clinic points out that many people don't know their blood pressure is high or that their cholesterol levels are up, but they do know if they overeat or don't exercise or smoke.

NISSEN: Despite all the warnings, smoking rates were once about 50 percent of the adult population in America. They are now down to about 20 or 25 percent. But that's still enough smoking - and particularly with secondhand smoke as well - to cause a lot of heart disease. And so, we know what causes it, we don't do as good a job as we would like to do as a society at controlling these risk factors.

WERTHEIMER: Dr. Nissen told us that while giving up smoking is difficult, it can be done. We can't control, he said, who our parents are. Heredity is the problem for another patient of Dr. Ken Lee's.

WERTHEIMER: He's had several heart surgeries including a valve replacement.

LEE: Big breath.

Valve sounds good.

SANCHEZ: Good.

WERTHEIMER: We saw Sanchez when came in for his monthly blood work and an EKG.

LEE: All right. Yeah, atrial fibrillation. Rates well-controlled though, so not too concerned about that. Are you aware that your heart rhythm is off a little bit today?

SANCHEZ: Yeah. I felt it this morning.

LEE: When did it pop up?

SANCHEZ: When I woke up.

LEE: Any shortness of breath?

SANCHEZ: No.

LEE: Chest discomfort, lightheadedness? Nothing like that?

SANCHEZ: No. I get it from time to time but that's...

LEE: It usually goes away pretty quickly?

SANCHEZ: Yeah. Yeah.

LEE: OK. Otherwise feeling OK?

SANCHEZ: Yeah.

LEE: All right. Good. I'm not going to put you on any additional medication. Since we've already got you on the Coumadin, you're protected.

WERTHEIMER: Coumadin is a blood thinner. Mr. Sanchez also takes statins, a low dose, in combination with other drugs. Dr. Lee told us all medication patients take has to be figured into their treatment plan.

LEE: When you get patients like Mr. Sanchez or Mr. Swendson, cholesterol is like having one bad tire out of four. If you just fix that one bad tire you really haven't corrected the problem. That's the art of cholesterol management and statin therapy.

WERTHEIMER: Statins were developed in the 1980s, and in the decades since, cholesterol levels in the United States have dropped. And deaths caused by heart disease have gone down dramatically. But recent studies show cholesterol levels have plateaued.

We asked Dr. Nissen what he thinks that means for the future use of statins.

NISSEN: For a long time, every time we looked, the cholesterol levels were a little bit lower. And that has leveled off to the point where cholesterol levels are now stable. However, I can tell you, every day patients come in our coronary care unit with a heart attack and we get their first cholesterol level and it is sky-high. And so I would argue that we have not maxed out the benefits of statins. There are lots of people, particularly in disadvantaged communities - particularly amongst minorities - and a lot of those people don't have access to preventive care and they - the first time they know they've got a cholesterol problem is when they come in with a heart attack, and that's really unfortunate.

WERTHEIMER: What is going to be the great leap forward that statins were?

NISSEN: I would say that we don't necessarily have a therapy waiting in the wings that is going to have quite the impact of statins. But we can't get everybody's cholesterol down and so there are new drugs, and you can give them with statins. And you can take somebody that has really high cholesterol levels and get them to really low levels. These drugs are moving along very quickly and they will mean that even the most tough and resistant high-cholesterol cases, we will have therapies available that can help those patients.

WERTHEIMER: What about high blood pressure - one of the other medical causes that has been very difficult to sort of back down?

NISSEN: Research on high blood pressure and new drugs for high blood pressure has stalled. We really don't have the magic bullet yet for that. But there is another area which is a very active area of research - very controversial - and that's drugs to raise HDL, the good cholesterol. It is my belief that one or more of these drugs is likely to work. And so the double-whammy of lowering the bad cholesterol, the LDL, and raising the good cholesterol, the HDL, is very attractive and if we can show that it works, it lets us take patients to even lower levels of risk.

WERTHEIMER: Dr. Steven Nissen is cardiology chair at the Cleveland Clinic. Thanks also to Dr. Ken Lee of Washington, D.C. and his patients.